When it rains, water runs over roadways, sidewalks, and buildings where it can pick up pollutants from cars, roofs, pet waste, yard care products, and more. This water is called stormwater and it can carry toxins that are harmful to fish and other aquatic animals in local waterways. Stormwater is the biggest source of pollution in Puget Sound.  

There is some evidence that filtering stormwater through crushed oyster shells can reduce heavy metals like copper and zinc. A pilot project run by King County and the City of Mercer Island is in place for two years to evaluate the effectiveness of crushed oyster shells on cleaning stormwater. Two storm drains have been retrofitted to include coarsely crushed oyster shells and another two are functioning as controls. Each of these four storm drains are connected to an above-ground sampling box (utility box) which contains specialized equipment that tests the quality of the stormwater. 

Since the project is in the downtown area of the Seattle suburb of Mercer Island with foot and car traffic, it is an ideal opportunity to provide public awareness and education about stormwater; the importance of protecting water quality; and a call to action for residents to change behavior – plus the utility boxes provided public art (using Mercer Island’s existing color templates) instead of becoming an eyesore. 

The boxes are wrapped in interpretive signage that informs local residents about stormwater pollution, shares information about this pilot program, and offers a call to action for specific behavior changes residents can make to reduce pollutants in stormwater, ultimately protecting Puget Sound.  

The side of each box that faces the street contains the simple message “What do oyster shells have to do with clean water?” in 300 pt. text, which sees an average daily traffic volume of approximately 8,000 vehicles. The intention behind this question is to pique the drivers’ and passengers’ interest to read the other panels the next time they are walking through the area to visit businesses, bus stops and restaurants. 

The front (door) panels contain the main message about the program and includes informative text in Spanish, Chinese, and Russian, logos and a web address for more info. The designer integrated the utility boxes’ physical features into the design. For example, the panel that is a door contains a vent toward the bottom. Rather than being a disruptive feature, the designer turned the vents into a graphic of a storm drain with a photo of crushed oyster shells underneath. Other graphics were added to show common pollutants of stormwater.

The side of the boxes that face the businesses have information about what we can all do to keep stormwater from getting polluted in icon-style graphics and minimal text. The back panels face lamp posts and contain artwork with clean water themes from local King County schoolchildren.

The color palette and style of illustration was informed by the current town banners which hang from the adjacent lamp posts.

The City of Mercer Island tweeted about the project on March 16 received 3,316 impressions and 102 engagements.

The utility boxes were installed in March 2019 so data is limited on the engagement impact for the local community and social marketing outcomes.

Budget: $12,500 – approximately 65% was spent on the in-house designer’s time (covered through overhead) and the remaining 35% was paid in direct costs to an outside vendor to print the vinyl and wrap the boxes. Money was saved by repurposing utility boxes already owned by King County and having county staff do the installation.